In certain industries it is necessary to remove as much of an original environment from contact with a product as possible and to replace it with a new environment. Fat and oil containing foods, for example are very susceptible to attack from oxygen and can be preserved much longer in its absence. A near complete removal of oxygen from containers for storing oxygen-sensitive products has, until now required complex and/or expensive equipment and often has required specialized and/or expensive containers.
Oxygen removal has traditionally been accomplished by packaging under vacuum or with a combination of inert gas and vacuum, see U.S. Pat. No. 2,718,345 issued to Howard. Plungers have been disclosed in the prior art for use under these traditional removal processes, see U.S. Pat. No. 3,508,373 issued to Robinson; U.S. Pat. No. 2,412,167 issued to Minaker.
Other prior art discloses flushing with inert gas the uppermost portion of containers after the containers have been filled with material, see U.S. Pat. No. 2,240,655 issued to Kronquest; U.S. Pat. No. 2,768,487 issued to Day et al. In addition, there is disclosed in the prior art means for flushing empty containers with inert gas, see U.S. Pat. No. 4,140,159 issued to Demke.
One object of this invention is to provide an apparatus which imparts a controlled environment, such as nitrogen or another inert gas, to one or more containers containing material at or near atmospheric pressure prior to sealing. This allows the use of less expensive container materials than used for the vacuum-packaging devices of the prior art. A related object is to provide an apparatus which achieves the desired near-total atmospheric exchange or control without at any time subjecting the container walls to a vacuum.
Another object of the present invention is to provide such an apparatus for use in a continuous processing operation, which is mechanically simple, having few components and which is therefore economical and highly reliable.
Another object is to provide such an apparatus which is adapted for use with specific sizes and configurations of jars and other containers, including containers of different heights. A further related object is to provide such a system adapted use with containers of specific diameters.
These and other objects shall be apparent in light of the present specification.